Valve tappet and method of forming the same



"w. c. OSTERHOLM VALVE TAPPET AND METHOD OF FQRMING TEE SAME Filed Dec 14, 1925 vwawto'o Nil/M222 6. Offer/70M attozum i t and stem and having v Uh QAK PARK, ILLINOIS, ASSIGN 01%; T WILC'UX PROD'U'GTLWJ GURPURATION, (3F SAGINAW, MICHIGAN,

A CORPORATION OF MIGHIQ-AN.

VALVE TAPPET' AND METHU'D OF FORMING THE S.

a nea-no'n'ai a December 14. 1925.

The invention relates to the manufacture of valves, valve tappets and the like and has for its object the obtaining of a structure built up from a separately formed head properties particularly adapted for its use in internal combustion engines. The" present inventionis an improvement over that described .in my co pending application Serial Number 708,048,

it filed April 21, 1924.

w mechanical interlock suitable for its In. the prior application above referred to, the head and stem are united by mechanioal processes but I have now improved the construction by providing in addition to the of the parts a bond more securely holds them together in fixed relation. Furthermore. I have provided a tappet in which the head and shank are given different physical properties. each own function. the head having a hard wear-resisting surface and the which shank having greater strength and being 1 less brittle. These properties are imparted to the structure by selection of suitable finally subjecting the single heat treatment that is' fical for both materials.

In the drawings: I

Figure 1 illustrates the separate stem and ead and the method of uniting the same;

Figure 2is a plan view of the head:

Figure 3 is a plan view of the brazing ring; I Figure 4 is a longitudinal section through the completed tappet. The-head A of my improved tappet is preferablv made of malleable iron. which in its usual physical condition mav be formed into the shape illustrated in Figure 1 bv forg ing. casting or machining. The head is preferably formed the outer circumferential edge C of which is under cut to form a shoulder as illus trated. The bottom of the recess is curved inwardly and upwardly as indicated at D forming" the annular central portion or flange E. The central portion of the tappet contains the cup-shaped recess F communicating with the central aperture G extending through the head and forming the means for feeding the lubricant onto the associated cam with which the tappet cooperates.

The tappet stem H may be formed in various ways, but is preferably tubular as inthat of the flange E on said h while the f with an annular recess'R.

Serial No. WAGS.

dicated and has the lower end of the tubularportion flared outwardly as indicated at to extend in a plane substantiall transverse to the axis ead.

- In order to assemble the stem to thehead, the latter is placed in a suitable holder L ormer is held in a co-operating holder M, the arrangement being such as to permit pressure to be exerted between said he beginning of the as eIn-, bling operation it will be noted. from Figure 1 of the drawing, that t e ilared portion extend radially outward and lies substantiallv in a plane perpendicular to the axis of the stem.

As stated above. it is desirable to provide a bond between the head and stem and this is accomplished in the present instance by inserting a brazing material in,the recess The brazing material 1s 0. the outer diameter of to the inner diameter of the flange J and ameter being larger than the annular flange E. Thus the disc may be inserted in the recess B beneath the stem H; after which the pressure is applied to the holder M as heretofore described, forming a mechanical inter-locking of the parts in jacent said surface, inserting said stem into such a manner as toinclose the disc in the said head, placing a brazing material between joint. In order to complete the bond bethe same, applying endwise pressure to said tween the stem and head the assembled tapmembers whereby the end portion of said pet is heated to a brazing temperature, stem is forced into inter-locking engagement 7 whereupon the brass disc is melted and the with the undercut portion of said head memmolten brazing material distributed into the her and heating said head to effect a brazing crevices of the joint and upon solidificaof said head and stem. tion forms a brass film Q, as indicated in 2. The method of manufacturing valve 10 Figure 4.. tappets and the like comprising the separate 75 It is desirable that the valve tappet be forming of a head member and a tubular heat treated in order to harden the head and stem member, said stem member having an refine the stem and in the preferred process annular end portion which is relatively the heat treatment and the brazing are caroblique to a surface on said head member ried out simultaneously. The assembled and said head member being formed with a so tappets are therefore heated to a temperature recess having an undercut peripheral porsufficiently high to harden both the head and t-ion, inserting an annular hrass disc in thethe stem, this temperature also being suflirecess of said head having a diameter cient to melt the brazing material. To adapted to also fit within the annular end facilitate the brazing the tappet is momenportion of said stem, applying endwise prestarily withdrawn from the heating furnace sure to said members to expand said annular andemersed in a flux such as molten sodium end portion into conformity with said recess cyanide which readily enters the crevices of I, and heating said head to melt said brass disc the joint opened by the heating. The tappet and to distribute the molten brass between is then replaced in the heating furnace and the contacting portions of said members.

brought up to the required temperature, 3. The method of manufacturing valve after which it is quenched to harden the taptappets and the like comprising the separate t and to solidify the brazing material. forming of a head of malleable iron, and a a temperature used in the heat-treatment tubular stem of medium carbon steel, said depends upon the type of materials used, but head having an undercut recess and said where the head is of malleable iron and the stem having a co-operating annular end stein is a medium carbon steel having for portion, inserting said steminto said head example, of carbon. a suitable treatwith brazing material therebetween, applyment is toheat 'to 1550 F., and quench in ing endwise pressure to said members suflioil. This treatment imparts an extremely cient to force said end portion into interhard surface to the malleable head A and locking engagement with said undercut poralso hardens the stemH sufliciently toimpa'rt tion, heating the united head and stem to a wear-resisting qualities thereto. This temtemperature sufficient to melt said brazing vent overheating of the stem so that it will stem, and quenching the head portion of the 105 notbe unduly brittle. Thus with a single united product. heat treatment the head and stem are bonded 4. A tappet comprising a head member together and are also providede with de.- recessed to form a shoulder, a tubular stem sirable physical properties for insuring long provided with an annular flange at one end life under service requirements; thereof extending substantially in a plane The out r surface R of the stem H is erpendieular to the axis of said stem and ground in t e usual manner for engagement inter-locking with said shoulder, and a. film with the co-operating guide and the bottom of bonding material between the contacting surface S of the head is also ground to coportions of said head and stem. v operate with the cam. The method of as- 5. A tappet comprising a head member sembling the stem to the head results in the recessed to forma shoulder, a tubular stem ortion of the stem adjacent the head being provided with an annular flange at one end forced slightly inward thereby resulting inthereof extending substantially in a plane a clearance groove T. The tappet as above perpendicular to the axis of said stem an described is cheap to manufacture and has interlocking with said shoulder, and a brass the desirable physical properties for long film between adjacent portions of said stem life and useful service. and head forming a bond between the same. What I claim as my invention is 2-- 6. A'tappet comprising a disc head re- 1. The method, of manufacturing valve cessed to form an annular undercut shoultappets and the like comprising the separate der, an inwardly and upwardly extending forming of a head member and a tubular curved surface and ace tral concave surface stem member, said stem member having an having an, aperture centrally thereof, a tuannular end portion which is relatively bular stem provided with an annular flange oblique to a surface on said head member. at one end thereof extending substantially in and said head member being undercut ad a plane perpendicular to the axis and periphperature, however, is sufficiently low to prematerial, harden said head and refine .said

.into the body of metallic stem member, undercut recess therein, inserting brazing material into said recess, applying undercut shoulfiange being rounded as it merges the tubular stem -to -fit the said head, andia film of er, said curved surface of bonding material between head, said film being united to said undercut shoulder, sai inwardly extending curved surface and said-tappet stein.

l. A tappet comprising a disc head oi" hardened malleable iron. said head being der, an inwardly and curved surface, face having an stem of medium upwardly extending and a central concave suraperture therein, a tubular peripherally inter-locked with said undercut shoulder, said flange conorming to the'contour of said recess, and a brass film intermediate said flange and said head forming a bond between the interlocking portions of said members;

8. The method of manufacturing valve 't-appetsand the like comprising the separate forming of a metallic head member and a said head member having an endwise pressure to said members, whereby the end portion of said stem is forced into inter-locking engagement with the undercut portion of said head member and the brazing material is inclosed within the joint and subsequently heat treating theassembled members to'harden oneof the same and to form a brazed joint.

9. A tappet or the like comprising a head member recessed to form cut shoulder and a curved lower surface,

a tubular stem provided with an annular extending substan flange one end thereof said stem and tially in a plane and peripherally undercut shoulder,

cess, said stem and head.

10. The method of manufacturing a valve tappet which-consists in separately forming a metalliehead member and a metallic stem member, inser'ing a brazing material between said head member and the said stem member, locking the said head member and er together and subsethe said St8l11 -,,:1 1116H1b quently heat treating the assembled members to harden the same and to form a brazed joint between the same; g

11. The method of manufacturinga valve tappet which consists in separately forming a metallic head member and a metallic stem member, forming interlocking means on the said members, inserting a brazing material between the said members, locking the two members together with the brazing material therebetween, and subsequently heat treating the said members to harden the same and to form a brazed joint between the same. v

12. The method of manufacturing a valve separately forming and a metallic stem member, forming member, forming means on the stem mem b 1' adapted for interlocking engagement WILLIAM C. OSTERHOLM.

a shoulder on the head 

